[R-390] Cosmos PTO adjustment

[Bill Abate]

I'm tackling the Cosmos PTO for linearity adjustment.  I have Dave's 
article on how to do it but I'm having problems in finding out what tool 
to use.  Those darn small screws are hard to see especially at my age!! 
  I was able to determine (with an 8X magnifying glass!)that the cap 
screw is an Allen head cap screw.  The smallest allen wrench I have is 
.028" and it fits but jumps when I try to turn the screw.  I have no 
idea what standard sizes allen wrenches come in.  1/16" is way to big. 
1/32" is .032" but that does not seem like too much of a difference from 
the .028 that I have.

Anybody know what size wrench I should be looking for?

73,

Bill, K3PGB